The present invention relates to an electronic musical instrument, difference tone output apparatus, a program and a recording medium and in particular to an electronic musical instrument for reproducing a performance sound of a musical instrument such as a pipe organ installed in a stone building, difference tone output apparatus for reproducing the performance sound, a program which describes the performance processing, and a recording medium which records the program.
In a recent dry construction hall where a pipe organ is installed, measures such as a highly rigid trim of a hall, optimized pipe arrangement, specific registration of an organ, and introduction of a sound field support system which electronically interpolates the reverberation time are taken in order to reproduce a performance sound with a long reverberation time same at that in a stone church in the Middle Ages of Europe.
The problem with the highly rigid trim of a hall and introduction of a sound field support system results in higher costs and optimization of pipe arrangement is sometimes difficult due to limitation on the structure of the musical instrument.
A stone building has a long reverberation time even in a low register, so that a difference tone is easy to perceive from a performance sound. Here, the difference tone is a tone perceived by the auditory system and is a derivative tone heard by generation of a vibration (f1-f2) corresponding to a difference between the vibrations from a distortion on the resonance in an auditory organ (nonlinearity of the basement membrane in cochlear duct) when one hears different vibration frequency f1 (Hz) and f2 (Hz) by the same ear. Thus, in a stone building, a sound lower than that of the musical instrument itself is perceived with a delay time, which sounds as a “rich bass tone”.
However, according to the related art which reproduces a sound in a stone building in a dry construction hall, it is practically difficult to provide the interior of a building with the same sound characteristics as those of a stone building. Although it is possible to emphasize the bass tone through registration of an organ and a sound field support system, it is different from reinforcement using a difference tone so that an audience is not fully satisfied with the bass tone reproduced.